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Kyocera KY003UAA Replacement Battery 3.7V 650mAh Li-ion

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From $23.99 USD $29.99
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Replaces Kyocera KY003UAA battery for Kyocera mobile phones; restores charge capacity on devices with degraded original cells.
3.7V and 650mAh capacity supports standard smartphone operations—calls, messaging, apps—on compatible Kyocera devices without runtime loss.
Connector fits Kyocera phone battery slot; 53.70 x 34.80 x 3.80mm form factor matches OEM dimensions with flush seating.
Bench testing showed clean BMS handshake on first insertion; voltage held steady under call and standby loads without early cutoff.
On first use after installation, disable fast charging for one complete discharge-charge cycle so the fuel gauge IC recalibrates against this cell's discharge curve.
Delivery time

This product ships directly from our Manufacturer’s Warehouse and is usually delivered within 5 – 8 business days to your doorstep.

Discount: As a thank you for your patience, enjoy 5% off on your order
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Battery Care Tips

🔹 Getting Started

Charge your new battery fully before you use it for the first time. Over the next few charge cycles, run your device down to around 20% before you recharge—this helps the battery perform its best. After that, charge whenever you need to.

🔹 Keep It Healthy

Avoid letting your battery completely drain or staying plugged in constantly. Both extremes wear it out faster. Store the battery in a cool, dry place when you're not using it, since heat damages batteries quickly.

Delivery and Shipping

🔹 Most orders ship the next day, and we use FedEx, UPS, Purolator and other carriers to get them to you. Lithium batteries have to ship by ground only, not air or USPS. Make sure your address is right before you order, because if we have to send it back, you pay for shipping again.

Disclaimer

⚠️ Disclaimer: All product names, trademarks, and registered trademarks belong to their respective owners.

🔹 We use these names, brands, or model numbers only for identification and compatibility purposes.

Voltage

3.7V

Amp

650mAh

Kyocera KY003UAA — 3.7V Li-ion Replacement Battery

This is a 3.7V, 650mAh Li-ion cell built to replace the KY003UAA battery in compatible Kyocera smartphones. The original cell degrades over charge cycles, causing the phone to shut down early or refuse to charge. Swapping in a fresh cell restores normal voltage output and charge acceptance.

  • KY003UAA platform fit: Kyocera phones using this part number share the same 3.7V single-cell architecture, connector pinout, and BMS handshake requirements. The replacement cell matches those electrical parameters so the charge IC recognises the battery correctly on boot.
  • Bench tested on actual hardware: We cycled this cell through charge and discharge under load. The BMS engaged protection cutoffs at the correct low-voltage threshold, and the charge IC accepted a full charge cycle without fault flags.
  • Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before high-current charging begins on an uncalibrated cell.

Why the phone reports wrong battery percentage after a cell swap

The fuel gauge IC stores a learned discharge curve from the old cell. When a new cell goes in, that stored curve no longer matches reality — so the percentage reading drifts or jumps. Run one full discharge down to automatic shutdown, then charge uninterrupted to 100% without removing the cable. After that single calibration cycle, the coulomb counter resets its reference points against the new cell and percentage readings stabilise.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops sharply under the load spike from the modem radio or display backlight — a voltage cliff the gauge IC did not predict. The phone's cutoff circuit sees the instantaneous voltage drop below the safe threshold and trips before the displayed percentage reaches zero. It is not a faulty cell — it is an uncalibrated gauge reading a mismatch between stored curve and actual cell impedance. Complete one full calibration cycle and verify the phone holds voltage above 3.4V under screen-on load.

Replaces Part Numbers

KY003UAA

Technical Specifications

Voltage3.7V
Amp Hours650mAh
Capacity650mAh
Rate2.41Wh
Net Weight16g /0.56 oz
Gross Weight41g /1.45 oz
Approximate Weight41g /1.45 oz
Dimension 53.70 x 34.80 x 3.80mm

Product Highlights

  • Brand: Kyocera
  • Manufacturer: CS
  • Series: Standard
  • Color: Black
  • Product Type: Li-ion
  • Battery Type: Li-ion
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

My Kyocera phone won't turn on at all after the replacement battery sat in a drawer for a few months — is the battery dead?

The BMS locks out the cell when voltage drops below approximately 2.5V during storage — a protection against deep-discharge damage to the lithium chemistry. Connect the phone to a wall charger (not a PC USB port) and leave it for 20–30 minutes before attempting to power on. The charge IC needs to push a small trickle current into the cell before the BMS releases its lockout and allows normal charging to resume. If the charging indicator appears within that window, the cell is recovering — let it reach at least 3.6V before booting the phone.

Fast charging stopped working after I put in the new battery — the phone only charges slowly now.

On the first cycle after a cell swap, the USB negotiation or proprietary charge protocol can fall back to standard 5V charging because the BMS on the new cell has not yet completed a handshake with the phone's charge IC. This is normal behaviour, not a fault. Run one complete charge cycle at the slow rate, then unplug and replug the charger — the charge IC re-negotiates the protocol against a now-initialised BMS and fast charging typically resumes.

The battery percentage jumps around erratically — it reads 45%, then jumps to 60%, then drops back again.

The fuel gauge IC is reading against a discharge curve calibrated to the old, degraded cell — the new cell's impedance profile does not match that stored curve, so the coulomb counter produces inconsistent output. Drain the phone to automatic shutdown under normal use (calls, screen on), then charge in a single uninterrupted session to 100%. That full cycle forces the fuel gauge IC to rebuild its reference curve against the actual new cell, and percentage reporting should stabilise within one to two cycles after that.

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